The invention relates to a router and a method for providing isochronous data transfer and asynchronous data transfer on the basis of a predetermined protocol between devices of different network sections connected to the router.
Currently, there are commercially available devices that can transmit isochronous audio packets, isochronous video packets and IP-packets from an IEEE 1394-capable device to other IEEE 1394-capable devices that reside on the same IEEE 1394-bus as the transmitting device. IEEE 1394 is also known as firewire. IEEE 1394 is a standard for isochronous and asynchronous data transfer. There are different IEEE data transfer protocols, such as IEEE 1394, IEEE 1394a, IEEE 1394b, IEEE 1394c and IEEE 1394.1.
Devices connected to an IEEE 1394-bus incorporate a non-permanent device identification having n=6 bits. Therefore, current IEEE 1394-networks are limited to 63 devices and there is no isolation of devices to separate buses. All devices connected to an IEEE 1394-bus are exposed to all bus resets within this network section. As a consequence of a bus reset, the device-ID of each device is reset and each device gets a new device-ID. This means that the device-identification of each device in the network section is non-permanent and will change with each bus reset. A bus reset is triggered by any change of the network topology, such as adding a new device to the network.
In IEEE 1394.1 a bridge between IEEE 1394-buses is specified. The specified IEEE 1394.1 bridge does not provide for control over the transmission of asynchronous packets from one bus to another. Since IP-control messages are carried by asynchronous packets, the conventional IEEE 1394.1 bridge as specified does not allow for security measures to be put in place with regard to across bridge control over devices.
The conventional IEEE 1394.1 bridge as specified allows the transfer of isochronous and asynchronous data only if the devices are bridge-aware. Conventional devices are not capable of interpreting messages received from a bridge, such as an IEEE 1394.1-bridge. An IEEE 1394.1-bridge can provide an isochronous and asynchronous data transfer between devices of different network sections connected to the bridge only if the transmitting device which is connected to a first network section and a receiving device which is connected to a second network section are both bridge-aware. However, there is a plurality of devices in the field which are not bridge-aware.
Accordingly, it is an object of the present invention to provide a router and a method allowing isochronous and asynchronous data transfer between devices of different network sections wherein the devices do not have to be able to respond to messages from the router.